Is your Bathroom as Clean as it could be?

I grew bacteria and tested it against common antibacterial cleaners to find which one was the most effective.

Goals:

For my project, I decided to grow bacteria samples from the bathrooms around school, and to test the efficiency of three common bathroom cleaners that many people use in their houses against bacteria. The three antibacterial cleaners tested were Mr. Clean, Lysol and Clorox. The purpose for this experiment was to figure out what common antibacterial cleaner was the most effective against the most common bacteria found in bathrooms. To determine the outcome, I needed to take the bacteria from the bathrooms, grow the bacteria, conduct a gram-stain, then finally conduct the test in which I used the antibacterial cleaners. My hypothesis for the experiment was that Lysol would be the most effective, because Lysol is the most commonly purchased brand in the United States.
The main reason I wanted to do something like this and that led to the formation of this experiment was to expand my understanding to the world of bacteria. I wanted to know what to expect to find in a bathroom, and then I wanted to know how to pinpoint the species of bacteria I found. Through this project I will complete both of those things thanks to the gram stain and my results from the gram stain.

Discoveries:

For my experiment, I utilized nine agar plates to test the bacteria. I got bacteria from three different places in the bathroom, the sink knobs, the door knobs and the paper towel dispenser. Each of the areas grew bacteria pretty evenly, and there were over 30 colonies on each one. After running the gram stain, I found out that I had grown e. Coli, and Staphylococcus Aureus. e. Coli is a commonly found bacteria around bathrooms and even though the common person thinks that it is harmful, most types of e. Coli are not harmful at all. e. Coli is gram negative, meaning that it does not contain a large amount of peptidoglycan in its cell wall. An e. Coli cell is a rod shaped type of bacteria. Rod shaped is one of three shapes of bacteria, there is rod shaped, spirilla and cocci. (1) I also discovered that I grew Staphylococcus Aureus. This species of bacteria is commonly known as “Staph.” The shape of “staph” is cocci. This means that when observed under a microscope, the bacteria has a shape that is spherical. Staph is also rarely found as a single cell, even though it can live by itself. Usually in nature, staph is found in large colonies that form a triangle. (7)
When I looked under the microscope, I saw the e. Coli bacteria moving. It moved in seemingly random ways. I also was able to see what the cell looked like, it was long and rounded at both ends, it resembled a straight stick. I also observed the “Staph” bacteria under the microscope. When they were under the microscope, they were round purple balls. The purple was the color left over from the gram stain, not the actual color of the bacteria in nature. external image image?id=sRDRWWRI-3SHeBd50m_lr7w&w=505&h=331&rev=178&ac=1

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Once reviewing these results, my hypothesis was proved wrong. My hypothesis was that Lysol would kill the bacteria because it was one of the most well known cleaners in the United States, but in the end, Mr. Clean, a product that I expected to come in last in this experiment, was the best at killing the bacteria that was found in the bathroom. The Mr Clean overall average beat out any competitor by almost 5 mm, which is a rather big difference when it is on such a small scale.

Challenges:

For my experiment, the biggest challenge was forming an experiment that would successfully provide information on the subject matter. Once I was able to set it up, running the experiment went very smoothly. If I were to start this experience over again, I would like to try different antibacterial cleaners so I could get more results.

Looking Back:

Looking back on my experiment, I did well to answer all of the questions I had. I learned how to successfully conduct an experiment that is complex and has many different factors. I also learned how to run the process of a gram stain, something that I had no idea how to do before I started this experiment. I found it pretty interesting that Mr. Clean was the most efficient antibacterial cleaner, but what I found most surprising was the amount of bacteria that the cleaning fluid had affected. By no means did the cleaner kill all of the bacteria. It killed some, but none of the cleaners killed all of the bacteria that was in the affected area. The reason I wanted to do something like this for my project was that I could have done something that I knew a lot about, but I wanted to learn about something I’ve never dealt with before. Planning this experiment and conducting it have been a great experience for me because I have learned so much about how bacteria grow, and how to find the exact species of bacteria is present by running a gram stain and looking at a sample of it under a microscope.